As editorial director of Ladybird Books, Douglas Keen, who has died aged 95, was responsible for the first experience of reading of millions of children. For untold numbers of youngsters, too, these were the first books they owned themselves, since it was company policy to make them all pocket-money affordable. Their price was kept at 2/6d (12½p) for almost 30 years.

The Key Words Reading Scheme, featuring the suburban siblings Peter and Jane, together with their faithful dog Pat, has sold upwards of 85m copies. This series of 36 books was Keen's brainchild, as were the hugely popular and enduring Nature books and numerous other titles, including Learning With Mother, People at Work, all Ladybird's history and science books and the How It Works series (faithfully pastiched, in recent times, when the BBC, in collaboration with the publisher, brought out How It Works: Shopping on the Internet). "The idea was that they could be stocking fillers, or a birthday gift," Keen told me. "Eventually we were able to say that, whatever the subject, there was a Ladybird that would help with the homework."

Keen was born in Cheltenham, Gloucestershire. His father, who left the family home when his son was a small boy, was a market gardener. His mother supported the family by tailoring and millinery. Keen won a scholarship to the prestigious Pate's grammar school in the town and, already a great believer in the value of education, went on to study art and marketing at evening classes.

His first job was as a sign-writer in advertising, where he learned the importance of concise wording, grammatical accuracy and careful proof-checking, skills that were to become foundation stones for the high standard he set at Ladybird.

In 1936, he went to work for Wills & Hepworth, a printing firm based in Loughborough, Leicestershire, that specialised in catalogue and advertising work, mainly for the knitwear and shoe industries in nearby Nottingham. The second world war brought paper shortages and a downturn in commercial printing. To keep jobs and the presses rolling, the company began to produce the first Ladybirds, storybooks for small children that could, ingeniously, be printed on just one sheet of paper.

Keen met Margaret Jones in the late 1930s and married her in 1941. He was called up in the early 1940s and joined a mobile radar unit in the RAF, serving in Belgium and France from 1944, returning from the war in 1945. His employers continued to pay a stipend to his mother on the understanding that Keen would rejoin the firm once the war ended. He stayed until 1973, when Ladybird was bought out by Pearson Longman.

His own thirst for knowledge and belief in self-improvement were the basis of his enthusiasm for encouraging children to enjoy learning, whether about wild flowers, Oliver Cromwell or how magnets work. In 1948, using the kitchen table as his desk, Keen devised the first factual Ladybird. He made a mock-up of a book of British birds, with watercolours by his mother-in-law, drawings by his wife and text by himself, and took it to his boss, Jim Clegg. The resulting Nature books were to be the longest-running of the Ladybird series. Clegg and Keen now steered the company towards the educational publishing for which Ladybird was to become world-renowned.

Keen commissioned experts to write the books and a team of first-class artists to illustrate them. Frank Hampson (the creator of the Eagle's Dan Dare), CF Tunnicliffe, Harry Wingfield, John Berry and Martin Aitchison all became regulars at Keen's home at Stratford-upon-Avon, Warwickshire, where business was conducted genially over ample lunches supplied by Margaret. Even at the height of the firm's success, the entire editorial department (consisting of Keen and a part-time secretary) operated out of a small extension purpose-built at the back of his house. Many of the artists were to become lifelong friends. "Douglas was the best professional friend I ever had," Aitchison recalled, "gracious with his praise, tactful but firm."

At a conference in the early 1960s, Keen met an educationist called William Murray, who had made an extensive study of the building blocks - the key words - of language. Months later, Keen happened to be passing through Cheltenham, where Murray taught at a school for children with special needs, and decided to look him up. Over tea in the Queen's Hotel, the idea for the Key Words Reading Scheme was born. The world depicted in these books has been criticised latterly for its ingenuous depiction of middle-class family life, but in their time the books were radical in their departure from the rarefied boarding schools and boating adventures that had been part of the prevailing idiom of children's literature.

For Keen, the product of a broken working-class family, the books may have represented an aspirational ideal; the renewal and optimism of postwar England. His own home, purpose-built in 1953, where he lived until his death, was redolent of those in the books he created.

The Keens enjoyed a long and happy marriage and a mutual love of music, art and the beauty and wonder of the natural world. After his wife's death in 1999, Keen took solace in the writing of Richard Dawkins and in reading his daily Guardian. Despite the gender stereotyping of the earlier Ladybird books, he was no sexist. He encouraged his two daughters to obtain professional qualifications, and took pride in darning his own socks.

Keen was softly spoken and had an innate courtesy. He was startlingly good-looking, even as an old man (in youth he was often mistaken for Kirk Douglas). He was amused by the resurgence of interest in vintage Ladybird books that the internet has fostered, although it was a source of mild irritation to him that some collectors were more preoccupied with the early, rare - and therefore valuable - animal storybooks than in the learning-centred titles whose production had made up his professional life.

He is survived by his daughters, Jenny and Caroline, five grandchildren (one of whom, Georgie Birkett, is a children's illustrator), and two great-grandchildren.

• Douglas Henry George Keen, publisher, born October 27 1913; died November 6 2008